Zeqing Lu

Porcine lactoferrin-derived peptide LFP-20 protects intestinal barrier by maintaining tight junction complex and modulating inflammatory response

LFP-20, a 20-amino acid antimicrobial peptide in the N terminus of porcine lactoferrin, has antimicrobial and immunomodulatory activities. This study assessed the protective effects of LFP-20 on LPS-induced intestinal damage in a LPS-induced mouse model and in vitro, using intestinal porcine epithelial cell line 1 (IPEC-1) cells. LFP-20 prevented LPS-induced impairment in colon epithelium tissues, infiltration of macrophages or leukocytes, histological evidence of inflammation and increased levels of TNF-a, IL-6 and IFN-γ. LFP-20 increased the expression of zonula occludens-1, occludin and claudin-1 and reduced permeability as well as apoptosis of the colon in LPS-treated mice. In IPEC-1 cells, LFP-20 increased transepithelial electrical resistance and tight junction expression. Moreover, we found LFP-20 decreased the MyD88 and AKT levels to affect the NF-κB signaling pathway, to modulate inflammation response and tight junction networks in the processing of LPS stimulation. In summary, LFP-20 prevents the inflammatory response and disruption of tight junction structure induced by LPS, suggesting the potential use of LFP-20 as a prophylactic agent to protect intestinal barrier function.

Butyrate upregulates endogenous host defense peptides to enhance disease resistance in piglets via histone deacetylase inhibition

Butyrate has been used to treat different inflammatory disease with positive outcomes, the mechanisms by which butyrate exerts its anti-inflammatory effects remain largely undefined. Here we proposed a new mechanism that butyrate manipulate endogenous host defense peptides (HDPs) which contributes to the elimination of Escherichia coli O157:H7, and thus affects the alleviation of inflammation. An experiment in piglets treated with butyrate (0.2% of diets) 2 days before E. coli O157:H7 challenge was designed to investigate porcine HDP expression, inflammation and E. coli O157:H7 load in feces. The mechanisms underlying butyrate-induced HDP gene expression and the antibacterial activity and bacterial clearance of macrophage 3D4/2 cells in vitro were examined. Butyrate treatment (i) alleviated the clinical symptoms of E. coli O157:H7-induced hemolytic uremic syndrome (HUS) and the severity of intestinal inflammation; (ii) reduced the E. coli O157:H7 load in feces; (iii) significantly upregulated multiple, but not all, HDPs in vitro and in vivo via histone deacetylase (HDAC) inhibition; and (iv) enhanced the antibacterial activity and bacterial clearance of 3D4/2 cells. Our findings indicate that butyrate enhances disease resistance, promotes the clearance of E. coli O157:H7, and alleviates the clinical symptoms of HUS and inflammation, partially, by affecting HDP expression via HDAC inhibition.

Effects of casein glycomacropeptide supplementation on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses in Escherichia coli K88 challenged piglets

Casein glycomacropeptide (CGMP) is a bioactive peptide derived from milk with multiple functions. This study was aimed at evaluating the effects of CGMP as a potential feed additive on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses of Escherichia coli K88 (E. coli K88) challenged piglets. Eighteen weaning piglets were randomly assigned to three groups. Control group and K88 challenged group received a basal diet, and CGMP treated group received the basal diet supplemented with 1% of CGMP powder. The trail lasted for 12 days, K88 was orally administered to the piglets of K88 challenged group and CGMP treated group on days 8–10. The results showed that the diet containing 1% CGMP significantly alleviated the decrease in average daily gain (P < 0.05), increase in pathogenic bacteria amounts in intestinal contents (P < 0.05), intestinal morphology (P > 0.05) and barrier permeability damage (P < 0.05), and acute inflammatory response (P < 0.05) induced by E. coli K88 infection. In conclusion, CGMP supplementation in the diet protected the weaning piglets against E. coli K88 infection.

Cathelicidin-WA Improves Intestinal Epithelial Barrier Function and Enhances Host Defense against Enterohemorrhagic Escherichia coli O157:H7 Infection

Impaired epithelial barrier function disrupts immune homeostasis and increases inflammation in intestines, leading to many intestinal diseases. Cathelicidin peptides suppress intestinal inflammation and improve intestinal epithelial barrier function independently of their antimicrobial activity. In this study, we investigated the effects of Cathelicidin-WA (CWA) on intestinal epithelial barrier function, as well as the underlying mechanism, by using enterohemorrhagic Escherichia coli (EHEC)–infected mice and intestinal epithelial cells. The results showed that CWA attenuated EHEC-induced clinical symptoms and intestinal colitis, as did enrofloxacin (Enro). CWA decreased IL-6 production in the serum, jejunum, and colon of EHEC-infected mice. Additionally, CWA alleviated the EHEC-induced disruption of mucin-2 and goblet cells in the intestine. Interestingly, CWA increased the mucus layer thickness, which was associated with increasing expression of trefoil factor 3, in the jejunum of EHEC-infected mice. CWA increased the expression of tight junction proteins in the jejunum of EHEC-infected mice. Using intestinal epithelial cells and a Rac1 inhibitor in vitro, we demonstrated that the CWA-mediated increases in the tight junction proteins might depend on the Rac1 pathway. Furthermore, CWA improved the microbiota and short-chain fatty acid concentrations in the cecum of EHEC-infected mice. Although Enro and CWA had similar effects on intestinal inflammation, CWA was superior to Enro with regard to improving intestinal epithelial barrier and microbiota in the intestine. In conclusion, CWA attenuated EHEC-induced inflammation, intestinal epithelial barrier damage, and microbiota disruption in the intestine of mice, suggesting that CWA may be an effective therapy for many intestinal diseases.

Biogenic Nanoselenium Particles Effectively Attenuate Oxidative Stress-Induced Intestinal Epithelial Barrier Injury by Activating the Nrf2 Antioxidant Pathway

In the present study, a new form of selenium nanoparticle (biogenic nanoselenium (BNS) particles) was synthesized using bacteria. The protection of BNS particles against oxidative stress-induced intestinal barrier dysfunction and the inherent mechanisms of this process were investigated, and selenomethionine (SeMet) and chemically synthesized nanoselenium (Nano-Se) particles were used for comparison. Characterization of BNS particles revealed that they were monodispersed and homogeneous spheres, with an average size of 139.43 ± 7.44 nm. In the mouse model of intestinal oxidative stress, BNS particles were found to protect the mouse intestinal barrier function and preserve intestinal redox homeostasis more efficiently than SeMet and Nano-Se. In vitro experiments with porcine jejunum epithelial (IPEC-J2) cells verified the stronger epithelial barrier-protecting effect of BNS particles against oxidative stress, with reduced cell apoptosis and an improved cell redox state. BNS activated the nuclear factor (erythroid-derived-2)-like 2 (Nrf2) and increased the expression of its downstream genes, including thioredoxin reductase (TXNRD)-1, NADPH dehydrogenase (NQO)-1, heme oxygenase (HO)-1, and thioredoxin (Trx), in dose- and time-dependent manners. In contrast, SeMet and Nano-Se merely enhanced the activity of the selenoenzymes TXNRD-1 and glutathione peroxidase (GPx)-1, indicating the role of selenium donors. Moreover, the knock down of Nrf2 significantly blocked the antioxidative effect of BNS, confirming that BNS protects the intestinal barrier from oxidative stress-induced damage by activating Nrf2 and its downstream genes. Our results suggest that BNS is a promising selenium species with potential application in treating oxidative stress-related intestinal diseases.

Aerobic biogenesis of selenium nanoparticles by Enterobacter cloacae Z0206 as a consequence of fumarate reductase mediated selenite reduction

In the present study, we examined the ability of Enterobacter cloacae Z0206 to reduce toxic sodium selenite and mechanism of this process. E. cloacae Z0206 was found to completely reduce up to 10u2009mM selenite to elemental selenium (Se°) and form selenium nanoparticles (SeNPs) under aerobic conditions. The selenite reducing effector of E. cloacae Z0206 cell was to be a membrane-localized enzyme. iTRAQ proteomic analysis revealed that selenite induced a significant increase in the expression of fumarate reductase. Furthermore, the addition of fumarate to the broth and knockout of fumarate reductase (frd) both significantly decreased the selenite reduction rate, which revealed a previously unrecognized role of E. cloacae Z0206 fumarate reductase in selenite reduction. In contrast, glutathione-mediated Painter-type reactions were not the main pathway of selenite reducing. In conclusion, E. cloacae Z0206 effectively reduced selenite to Se° using fumarate reductase and formed SeNPs; this capability may be employed to develop a bioreactor for treating Se pollution and for the biosynthesis of SeNPs in the future.

Amino acid and phosphorus digestibility of fermented corn-soybean meal mixed feed with and fed to pigs

In the present study, a 2-stage solid-state fermentation process using followed by was performed with the purpose of improving the nutritional quality of corn and soybean meal (SBM) mixed feed (MF). The matrix of native MF and fermented MF (FMF) was analyzed using scanning electron microscopy to determine external structures after solid-state fermentation. Results of the present study indicated that the FMF had a greater concentration of CP and total P compared with the unfermented feed, whereas the contents of β-conglycinin, glycinin, phytate P, raffinose, stachyose, and NDF in FMF declined by 77.6, 86.7, 41.2, 47.2, 36.6, and 38.9%, respectively. The content of trichloroacetic acid-soluble protein, particularly those of small peptides and free AA, increased more than 3 times after fermentation. Scanning electron microscopy revealed that irregular shapes and a lot of porous structures were observed in the SBM of FMF, the cell wall of corn in FMF was destroyed, and the number of starch granules was decreased after 2-stage fermentation. Two animal experiments were conducted to evaluate the digestibility of CP and P in FMF when fed to pigs. In Exp. 1, 6 barrows (15.20 ± 1.27 kg initial BW) fitted with a T-cannula in the distal ileum were allotted to a replicated 3 × 3 Latin square with 3 diets and 3 periods per square. Two diets containing unfermented MF or FMF as the only source of protein and a N-free diet were formulated. Results indicated that the apparent ileal digestibility (AID) of total AA and Lys in FMF (74.98 and 75.34%) were greater ( < 0.05) than in untreated MF (69.66 and 68.56%). The standard ileal digestibility (SID) of Lys in FMF (82.17%) was also greater ( < 0.05) than in MF (75.91%). In Exp. 2, 16 barrows (17.57 ± 1.08 kg initial BW) were allotted to 2 diets formulated to contain MF or FMF as the sole source of P to determine the digestibility of P. The apparent total tract digestibility and standardized total tract digestibility of P in FMF were 58.14 and 64.72%, respectively. These values were greater ( < 0.01) than in untreated MF (37.11 and 44.89%, respectively). Our results indicate that a solid-state fermentation process using followed by offers an effective approach to improving the quality of corn and SBM MF.

Effects of supplementing sow diets with fermented corn and soybean meal mixed feed during lactation on the performance of sows and progeny

In the present study, two experiments were performed to study the effects of feeding fermented corn and soybean meal mixed feed (FMF) with Bacillus subtilis and Enterococcus faecium to lactating sows on the performance of the sows and their progeny. In experiment 1, 60 sows were allocated to the following three dietary treatments: 1) sows fed a corn and soybean meal basal diet (control) from day 3 before parturition to weaning, 2) sows fed a diet with 7.5% FMF, and 3) sows fed a diet with 15% FMF. Results indicated that feeding 15% FMF significantly improved (P < 0.05) the sows ADFI, the individual piglet weaning weights, and piglet weight gain and reduced (P < 0.05) the backfat loss of sows compared with the control group. However, the 7.5% FMF treatment did not alter the performance of the sows or their progeny. Therefore, we considered the level of 15% FMF to be more efficient than 7.5% FMF. To verify the results of experiment 1, we performed experiment 2, in which 60 sows at 111 d of gestation were allocated into the following two dietary treatments: 1) sows fed a basal lactation diet (control) from d 111 of gestation to weaning and 2) sows fed a basal diet with 15% FMF. Compared with the control group, 15% FMF inclusion significantly increased (P < 0.05) the sows ADFI, litter weight gain, and individual piglet weight gain during lactation and markedly decreased the backfat loss of sows (P < 0.05) and piglet diarrhea incidence (P < 0.05). Additionally, the milk yield and IgA contents of the milk in sows fed 15% FMF were greater (P < 0.05) than those of the control group. Furthermore, the apparent total tract digestibility of GE, DM, and total P of sows was increased (P < 0.05) with 15% FMF supplementation. Therefore, the present study indicates that supplementing sow diets with 15% FMF from parturition to weaning has the potential to 1) increase sow ADFI, milk production, milk IgA content, and nutrient digestibility and promote sow reproductive performance by shortening the weaning-to-estrous interval and 2) promote the growth performance of their progeny and decrease diarrhea incidence.

Antimicrobial resistance in livestock: antimicrobial peptides provide a new solution for a growing challenge

• The rise in antimicrobial resistance is widely acknowledged as a result of misuse and overuse of livestock antibiotics. Once transferred to human beings, these strains can cause diseases that are not treatable by antibiotics. • Antibiotics can largely accumulate in the environment through livestock excretion and eventually threaten public health. • Current government regulations on antibiotics cannot effectively and immediately stop the increase in antimicrobial resistance. There is an urgent need to find alternatives that do not lead to resistance in the future. • Antimicrobial peptides hold promise as effective alternative as they have efficacious antimicrobial effects and weak resistance induction ability. Feature Article Antimicrobial resistance in livestock: antimicrobial peptides provide a new solution for a growing challenge